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Date: Sun, 30 Aug 2009 01:50:51 -0700
From: Marcel Holtmann <marcel@...tmann.org>
To: "David S. Miller" <davem@...emloft.net>
Cc: netdev@...r.kernel.org
Subject: [PATCH 37/47] Bluetooth: Add support for L2CAP SREJ exception
From: Gustavo F. Padovan <gustavo@....ic.unicamp.br>
When L2CAP loses an I-frame we send a SREJ frame to the transmitter side
requesting the lost packet. This patch implement all Recv I-frame events
on SREJ_SENT state table except the ones that deal with SendRej (the REJ
exception at receiver side is yet not implemented).
Signed-off-by: Gustavo F. Padovan <gustavo@....ic.unicamp.br>
Signed-off-by: Marcel Holtmann <marcel@...tmann.org>
---
include/net/bluetooth/bluetooth.h | 1 +
include/net/bluetooth/l2cap.h | 14 ++-
net/bluetooth/l2cap.c | 220 +++++++++++++++++++++++++++++++++----
3 files changed, 210 insertions(+), 25 deletions(-)
diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index b8b9a84..718394e 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -140,6 +140,7 @@ struct bt_skb_cb {
__u8 incoming;
__u8 tx_seq;
__u8 retries;
+ __u8 sar;
};
#define bt_cb(skb) ((struct bt_skb_cb *)((skb)->cb))
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 59b26bf..9f2126a 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -108,6 +108,7 @@ struct l2cap_conninfo {
#define L2CAP_CTRL_TXSEQ_SHIFT 1
#define L2CAP_CTRL_REQSEQ_SHIFT 8
+#define L2CAP_CTRL_SAR_SHIFT 14
/* L2CAP Supervisory Function */
#define L2CAP_SUPER_RCV_READY 0x0000
@@ -290,6 +291,13 @@ struct l2cap_conn {
/* ----- L2CAP channel and socket info ----- */
#define l2cap_pi(sk) ((struct l2cap_pinfo *) sk)
#define TX_QUEUE(sk) (&l2cap_pi(sk)->tx_queue)
+#define SREJ_QUEUE(sk) (&l2cap_pi(sk)->srej_queue)
+#define SREJ_LIST(sk) (&l2cap_pi(sk)->srej_l.list)
+
+struct srej_list {
+ __u8 tx_seq;
+ struct list_head list;
+};
struct l2cap_pinfo {
struct bt_sock bt;
@@ -318,6 +326,8 @@ struct l2cap_pinfo {
__u8 expected_ack_seq;
__u8 req_seq;
__u8 expected_tx_seq;
+ __u8 buffer_seq;
+ __u8 buffer_seq_srej;
__u8 unacked_frames;
__u8 retry_count;
__u8 num_to_ack;
@@ -338,6 +348,8 @@ struct l2cap_pinfo {
struct timer_list retrans_timer;
struct timer_list monitor_timer;
struct sk_buff_head tx_queue;
+ struct sk_buff_head srej_queue;
+ struct srej_list srej_l;
struct l2cap_conn *conn;
struct sock *next_c;
struct sock *prev_c;
@@ -356,7 +368,7 @@ struct l2cap_pinfo {
#define L2CAP_CONF_MAX_CONF_RSP 2
#define L2CAP_CONN_SAR_SDU 0x01
-#define L2CAP_CONN_UNDER_REJ 0x02
+#define L2CAP_CONN_SREJ_SENT 0x02
#define L2CAP_CONN_WAIT_F 0x04
#define __mod_retrans_timer() mod_timer(&l2cap_pi(sk)->retrans_timer, \
diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
index 4c31900..70aff92 100644
--- a/net/bluetooth/l2cap.c
+++ b/net/bluetooth/l2cap.c
@@ -1292,6 +1292,50 @@ static int l2cap_streaming_send(struct sock *sk)
return 0;
}
+static int l2cap_retransmit_frame(struct sock *sk, u8 tx_seq)
+{
+ struct l2cap_pinfo *pi = l2cap_pi(sk);
+ struct sk_buff *skb, *tx_skb;
+ u16 control, fcs;
+ int err;
+
+ skb = skb_peek(TX_QUEUE(sk));
+ do {
+ if (bt_cb(skb)->tx_seq != tx_seq) {
+ if (skb_queue_is_last(TX_QUEUE(sk), skb))
+ break;
+ skb = skb_queue_next(TX_QUEUE(sk), skb);
+ continue;
+ }
+
+ if (pi->remote_max_tx &&
+ bt_cb(skb)->retries == pi->remote_max_tx) {
+ l2cap_send_disconn_req(pi->conn, sk);
+ break;
+ }
+
+ tx_skb = skb_clone(skb, GFP_ATOMIC);
+ bt_cb(skb)->retries++;
+ control = get_unaligned_le16(tx_skb->data + L2CAP_HDR_SIZE);
+ control |= (pi->req_seq << L2CAP_CTRL_REQSEQ_SHIFT)
+ | (tx_seq << L2CAP_CTRL_TXSEQ_SHIFT);
+ put_unaligned_le16(control, tx_skb->data + L2CAP_HDR_SIZE);
+
+ if (l2cap_pi(sk)->fcs == L2CAP_FCS_CRC16) {
+ fcs = crc16(0, (u8 *)tx_skb->data, tx_skb->len - 2);
+ put_unaligned_le16(fcs, tx_skb->data + tx_skb->len - 2);
+ }
+
+ err = l2cap_do_send(sk, tx_skb);
+ if (err < 0) {
+ l2cap_send_disconn_req(pi->conn, sk);
+ return err;
+ }
+ break;
+ } while(1);
+ return 0;
+}
+
static int l2cap_ertm_send(struct sock *sk)
{
struct sk_buff *skb, *tx_skb;
@@ -2705,6 +2749,7 @@ static inline int l2cap_config_req(struct l2cap_conn *conn, struct l2cap_cmd_hdr
l2cap_monitor_timeout, (unsigned long) sk);
__skb_queue_head_init(TX_QUEUE(sk));
+ __skb_queue_head_init(SREJ_QUEUE(sk));
l2cap_chan_ready(sk);
goto unlock;
}
@@ -2784,8 +2829,10 @@ static inline int l2cap_config_rsp(struct l2cap_conn *conn, struct l2cap_cmd_hdr
sk->sk_state = BT_CONNECTED;
l2cap_pi(sk)->expected_tx_seq = 0;
+ l2cap_pi(sk)->buffer_seq = 0;
l2cap_pi(sk)->num_to_ack = 0;
__skb_queue_head_init(TX_QUEUE(sk));
+ __skb_queue_head_init(SREJ_QUEUE(sk));
l2cap_chan_ready(sk);
}
@@ -2817,6 +2864,7 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, struct l2cap_cmd
sk->sk_shutdown = SHUTDOWN_MASK;
skb_queue_purge(TX_QUEUE(sk));
+ skb_queue_purge(SREJ_QUEUE(sk));
del_timer(&l2cap_pi(sk)->retrans_timer);
del_timer(&l2cap_pi(sk)->monitor_timer);
@@ -2843,6 +2891,7 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn, struct l2cap_cmd
return 0;
skb_queue_purge(TX_QUEUE(sk));
+ skb_queue_purge(SREJ_QUEUE(sk));
del_timer(&l2cap_pi(sk)->retrans_timer);
del_timer(&l2cap_pi(sk)->monitor_timer);
@@ -3038,6 +3087,33 @@ static int l2cap_check_fcs(struct l2cap_pinfo *pi, struct sk_buff *skb)
return 0;
}
+static void l2cap_add_to_srej_queue(struct sock *sk, struct sk_buff *skb, u8 tx_seq, u8 sar)
+{
+ struct sk_buff *next_skb;
+
+ bt_cb(skb)->tx_seq = tx_seq;
+ bt_cb(skb)->sar = sar;
+
+ next_skb = skb_peek(SREJ_QUEUE(sk));
+ if (!next_skb) {
+ __skb_queue_tail(SREJ_QUEUE(sk), skb);
+ return;
+ }
+
+ do {
+ if (bt_cb(next_skb)->tx_seq > tx_seq) {
+ __skb_queue_before(SREJ_QUEUE(sk), next_skb, skb);
+ return;
+ }
+
+ if (skb_queue_is_last(SREJ_QUEUE(sk), next_skb))
+ break;
+
+ } while((next_skb = skb_queue_next(SREJ_QUEUE(sk), next_skb)));
+
+ __skb_queue_tail(SREJ_QUEUE(sk), skb);
+}
+
static int l2cap_sar_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 control)
{
struct l2cap_pinfo *pi = l2cap_pi(sk);
@@ -3118,50 +3194,143 @@ static int l2cap_sar_reassembly_sdu(struct sock *sk, struct sk_buff *skb, u16 co
return err;
}
+static void l2cap_check_srej_gap(struct sock *sk, u8 tx_seq)
+{
+ struct sk_buff *skb;
+ u16 control = 0;
+
+ while((skb = skb_peek(SREJ_QUEUE(sk)))) {
+ if (bt_cb(skb)->tx_seq != tx_seq)
+ break;
+
+ skb = skb_dequeue(SREJ_QUEUE(sk));
+ control |= bt_cb(skb)->sar << L2CAP_CTRL_SAR_SHIFT;
+ l2cap_sar_reassembly_sdu(sk, skb, control);
+ l2cap_pi(sk)->buffer_seq_srej =
+ (l2cap_pi(sk)->buffer_seq_srej + 1) % 64;
+ tx_seq++;
+ }
+}
+
+static void l2cap_resend_srejframe(struct sock *sk, u8 tx_seq)
+{
+ struct l2cap_pinfo *pi = l2cap_pi(sk);
+ struct srej_list *l, *tmp;
+ u16 control;
+
+ list_for_each_entry_safe(l,tmp, SREJ_LIST(sk), list) {
+ if (l->tx_seq == tx_seq) {
+ list_del(&l->list);
+ kfree(l);
+ return;
+ }
+ control = L2CAP_SUPER_SELECT_REJECT;
+ control |= l->tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
+ l2cap_send_sframe(pi, control);
+ list_del(&l->list);
+ list_add_tail(&l->list, SREJ_LIST(sk));
+ }
+}
+
+static void l2cap_send_srejframe(struct sock *sk, u8 tx_seq)
+{
+ struct l2cap_pinfo *pi = l2cap_pi(sk);
+ struct srej_list *new;
+ u16 control;
+
+ while (tx_seq != pi->expected_tx_seq) {
+ control = L2CAP_SUPER_SELECT_REJECT;
+ control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
+ l2cap_send_sframe(pi, control);
+
+ new = kzalloc(sizeof(struct srej_list), GFP_ATOMIC);
+ new->tx_seq = pi->expected_tx_seq++;
+ list_add_tail(&new->list, SREJ_LIST(sk));
+ }
+ pi->expected_tx_seq++;
+}
+
static inline int l2cap_data_channel_iframe(struct sock *sk, u16 rx_control, struct sk_buff *skb)
{
struct l2cap_pinfo *pi = l2cap_pi(sk);
u8 tx_seq = __get_txseq(rx_control);
u16 tx_control = 0;
+ u8 sar = rx_control >> L2CAP_CTRL_SAR_SHIFT;
int err = 0;
BT_DBG("sk %p rx_control 0x%4.4x len %d", sk, rx_control, skb->len);
- if (tx_seq == pi->expected_tx_seq) {
- if (pi->conn_state & L2CAP_CONN_UNDER_REJ)
- pi->conn_state &= ~L2CAP_CONN_UNDER_REJ;
+ if (tx_seq == pi->expected_tx_seq)
+ goto expected;
- err = l2cap_sar_reassembly_sdu(sk, skb, rx_control);
- if (err < 0)
- return err;
+ if (pi->conn_state & L2CAP_CONN_SREJ_SENT) {
+ struct srej_list *first;
- pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
- pi->num_to_ack = (pi->num_to_ack + 1) % L2CAP_DEFAULT_NUM_TO_ACK;
- if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) {
- tx_control |= L2CAP_SUPER_RCV_READY;
- tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
- goto send;
+ first = list_first_entry(SREJ_LIST(sk),
+ struct srej_list, list);
+ if (tx_seq == first->tx_seq) {
+ l2cap_add_to_srej_queue(sk, skb, tx_seq, sar);
+ l2cap_check_srej_gap(sk, tx_seq);
+
+ list_del(&first->list);
+ kfree(first);
+
+ if (list_empty(SREJ_LIST(sk))) {
+ pi->buffer_seq = pi->buffer_seq_srej;
+ pi->conn_state &= ~L2CAP_CONN_SREJ_SENT;
+ }
+ } else {
+ struct srej_list *l;
+ l2cap_add_to_srej_queue(sk, skb, tx_seq, sar);
+
+ list_for_each_entry(l, SREJ_LIST(sk), list) {
+ if (l->tx_seq == tx_seq) {
+ l2cap_resend_srejframe(sk, tx_seq);
+ return 0;
+ }
+ }
+ l2cap_send_srejframe(sk, tx_seq);
}
} else {
- /* Unexpected txSeq. Send a REJ S-frame */
- kfree_skb(skb);
- if (!(pi->conn_state & L2CAP_CONN_UNDER_REJ)) {
- tx_control |= L2CAP_SUPER_REJECT;
- tx_control |= pi->expected_tx_seq << L2CAP_CTRL_REQSEQ_SHIFT;
- pi->conn_state |= L2CAP_CONN_UNDER_REJ;
+ pi->conn_state |= L2CAP_CONN_SREJ_SENT;
- goto send;
- }
+ INIT_LIST_HEAD(SREJ_LIST(sk));
+ pi->buffer_seq_srej = pi->buffer_seq;
+
+ __skb_queue_head_init(SREJ_QUEUE(sk));
+ l2cap_add_to_srej_queue(sk, skb, tx_seq, sar);
+
+ l2cap_send_srejframe(sk, tx_seq);
}
return 0;
-send:
- return l2cap_send_sframe(pi, tx_control);
+expected:
+ pi->expected_tx_seq = (pi->expected_tx_seq + 1) % 64;
+
+ if (pi->conn_state & L2CAP_CONN_SREJ_SENT) {
+ l2cap_add_to_srej_queue(sk, skb, tx_seq, sar);
+ return 0;
+ }
+
+ pi->buffer_seq = (pi->buffer_seq + 1) % 64;
+
+ err = l2cap_sar_reassembly_sdu(sk, skb, rx_control);
+ if (err < 0)
+ return err;
+
+ pi->num_to_ack = (pi->num_to_ack + 1) % L2CAP_DEFAULT_NUM_TO_ACK;
+ if (pi->num_to_ack == L2CAP_DEFAULT_NUM_TO_ACK - 1) {
+ tx_control |= L2CAP_SUPER_RCV_READY;
+ tx_control |= pi->buffer_seq << L2CAP_CTRL_REQSEQ_SHIFT;
+ l2cap_send_sframe(pi, tx_control);
+ }
+ return 0;
}
static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, struct sk_buff *skb)
{
struct l2cap_pinfo *pi = l2cap_pi(sk);
+ u8 tx_seq = __get_reqseq(rx_control);
BT_DBG("sk %p rx_control 0x%4.4x len %d", sk, rx_control, skb->len);
@@ -3181,7 +3350,7 @@ static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, str
if (pi->unacked_frames > 0)
__mod_retrans_timer();
} else {
- pi->expected_ack_seq = __get_reqseq(rx_control);
+ pi->expected_ack_seq = tx_seq;
l2cap_drop_acked_frames(sk);
if (pi->unacked_frames > 0)
__mod_retrans_timer();
@@ -3200,8 +3369,11 @@ static inline int l2cap_data_channel_sframe(struct sock *sk, u16 rx_control, str
break;
- case L2CAP_SUPER_RCV_NOT_READY:
case L2CAP_SUPER_SELECT_REJECT:
+ l2cap_retransmit_frame(sk, tx_seq);
+ break;
+
+ case L2CAP_SUPER_RCV_NOT_READY:
break;
}
--
1.6.2.5
--
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